Storage tanks for holding bulk quantities of liquid are used throughout industry. Gasoline service stations make wide use of underground storage tanks which hold from about 10,000 to 40,000 gallons of gasoline. These tanks are filled periodically from transport trucks. Usually a fill connection is found at ground level for easy filling. A delivery hose is simply connected to the fill connector and gasoline pumped from the truck to the tank. Automatic shut-off valves ensure that dispensing of the gasoline is controlled. However, faulty delivery hoses, poor line connections or even operator error can result in gasoline being spilled at the fill connection. Any spill is generally small and is readily absorbed into the environment. However, continued spilling over a period of time or one large spill poses a substantial health hazard.
Various devices have been suggested for use in minimizing gasoline spills during a filling operation. U.S. Pat. Nos. 3,732,902, 4,204,564, 4,457,349 and 4,615362 disclose overfill pits and tanks of various designs. None, however, have proven to be completely satisfactory. Any overfill tank must be capable of ready attachment to a storage tank and be reliable. In particular, stress points which can lead to cracking or potential sources of spill leakage must be eliminated. Additionally, access to the interior of the overfill tank for filling purposes must be readily accomplished. Because a transport tank is restricted a to where it can park for unloading, the fill tank's delivery hose may lead to the overfill tank from any direction. Access to the fill connections of any overfill tank must be able to accomodate such delivery hoses.
There has now been developed an overfill assembly which is economical to produce, yet which fills a long felt need. The assembly has a minimum of connections so as to reduce substantially any possibility for early failure. Additionally, the assembly is readily installed on a storage tank.